Compilare: main.cpp: In function 'int main()': main.cpp:36:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<a.size(); i++) ~^~~~~~~~~ main.cpp:18:23: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&n); ^ main.cpp:21:27: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&x); ^